Surface contamination is a widespread concern in many industries. Such contamination can result in production of inferior or non-operating products, or considerably lower product yields. For instance, as a specific example, surface contamination is a prevalent problem in the microelectronics processing industry, and can take the form of unwanted particles, films, molecules, or the like; and the surfaces that can be contaminated include those of semiconductor wafers, displays, microelectronic components, etc. Contamination of these surfaces can cause various types of defects to develop, including short circuits, open circuits, stacking faults, among others. These defects can adversely affect circuits, and ultimately cause entire chips to fail.
Another type of surface that has contaminants that are required to be removed are the walls of tool or processing chambers, such as plasma etch and chemical vapor deposition reactors. Reaction residues and/or polymers generated during semiconductor processing tend to deposit on the chamber walls. These residues and/or polymers can subsequently flake off onto products being processed or onto subsequently processed products. In order to prevent yield loss due to this mechanism, manufacturing processing chambers have to be disassembled periodically to be cleaned or "wiped down". Current practice involves weekly disassembly of the fixtures inside the chamber and wipe down of all the surfaces with a mixture of alcohol and water. This periodic machine disassembly, wipe down, and re-assembly, and the required long pump-down times after cleaning for surface drying, severely reduces the production and reliability of the processing equipment. In addition, the acidic fumes formed when the deposited material reacts with water often creates a health hazard for cleaning personnel.
U.S. Pat. No. 5,108,512, issued Apr. 28, 1992, to Goffnett et al., relates to cleaning a chemical vapor deposition reactor used in the production of polycrystalline silicon by impacting with carbon dioxide pellets. Goffnett et al. discloses delivering carbon dioxide gas to a pelletizer where the gas is compressed and formed into solid carbon dioxide pellets. The pellets, along with an accelerant gas for increasing the velocity of the pellets, are delivered to a nozzle. The nozzle is a "venturi" nozzle which maximizes the velocity at which the pellets are emitted therefrom. Further, the nozzle is mounted on a conveyor arm which allows movement of the nozzle. Disadvantages associated with the Goffnett et al. apparatus include the requirement of a pelletizer, and the mounting of the nozzle on a conveyor arm for movement of the nozzle. More specifically, the conveyor arm arrangement limits mobility of the nozzle since the nozzle can only be moved in accordance with the configuration of the conveyor arm.
Another form of cleaning includes chemical cleaning which is used for cleaning particulate and/or film contaminants from surfaces, such as wafers and substrates. Chemical cleaning involves using a solvent or liquid cleaning agent to dislodge or dissolve contaminants from the surface to be cleaned. A disadvantageous associated with chemical cleaning methods is that the cleaning agent must be maintained with a high degree of cleanliness and purity. Thus, a high quality agent is required, and the agent must be replaced periodically as it becomes progressively more contaminated during cleaning. The replaced chemicals require disposal and cause environmental degradation. Accordingly, it is difficult and expensive to appropriately and effectively implement chemical cleaning methods.
U.S. Pat. No. 5,062,898, issued Nov. 5, 1991, to McDermott et al., and commonly assigned to a co-assignee of the present invention, relates to a method of cleaning microelectronics surfaces using an aerosol of at least substantially solid argon particles which impinge upon the surface to be cleaned.
U.S. Ser. No. 07/970,346, filed Nov. 2, 1992, pending, and commonly assigned to a co-assignee of the present invention, relates to a method of cleaning microelectronics surfaces using an aerosol of at least substantially solid argon or nitrogen particles which impinge upon the surface to be cleaned.
U.S. Ser. No. 07/958,417, filed Oct. 9, 1992, allowed Dec. 14, 1992, and commonly assigned to a co-assignee of the present invention, relates to an apparatus capable of executing the process of cleaning with a cryogenic aerosol as described in U.S. Pat. No. 5,062,898 or U.S. Ser. No. 07/970,346.